Solve for $x$ and $y$ using substitution. ${-x+2y = -8}$ ${y = -x+5}$
Answer: Since $y$ has already been solved for, substitute $-x+5$ for $y$ in the first equation. ${-x + 2}{(-x+5)}{= -8}$ Simplify and solve for $x$ $-x-2x + 10 = -8$ $-3x+10 = -8$ $-3x+10{-10} = -8{-10}$ $-3x = -18$ $\dfrac{-3x}{{-3}} = \dfrac{-18}{{-3}}$ ${x = 6}$ Now that you know ${x = 6}$ , plug it back into $\thinspace {y = -x+5}\thinspace$ to find $y$ ${y = -}{(6)}{ + 5}$ $y = -6 + 5$ $y = -1$ You can also plug ${x = 6}$ into $\thinspace {-x+2y = -8}\thinspace$ and get the same answer for $y$ : ${-}{(6)}{ + 2y = -8}$ ${y = -1}$